1. Field of the Invention
The present invention relates to a cooking device in general, and especially relates to a built-in cooking device having a drawer body capable of storing therein an object to be cooked, and movably disposed within a cooking device body to be drawn out therefrom.
2. Description of the Related Art
A large number of cooking devices such as microwave ovens with an open/close door disposed on a front side thereof have been proposed, but on the other hand, another type of cooking device having a drawer that can be drawn out to the front side of the device has also been proposed. The drawer type cooking device can suitably be applied to relatively large-scale structures, so that it is considered as a cooking device constituting a part of a fitted kitchen or a designed kitchen. Reflecting the recent systemization and increase in size of kitchens, cooking devices have also been diversified and unitized, and various cooking devices being combined with cook tops, drawer-type microwave ovens, electric ovens and so on and built into kitchens are proposed.
The present applicant has proposed a drawer type cooking device having a cooking device body including a heating chamber, a drawer body disposed movably within the cooking device body 1 so as to be drawn out from within the heating chamber of the cooking device body, and a slide mechanism composed of a slide rail for moving the drawer body within the cooking device body, wherein the slide mechanism is disposed outside the heating chamber (patent document 1: Japanese patent application laid-open publication No. 2005-221081). According to the drawer type cooking device, the loading portion for loading an object to be heated in the heating chamber can be drawn out together with the door, so as to eliminate the need to form the slide mechanism using components or materials having high heat resistance and flame resistance, and to prevent the occurrence of microwave discharge failure caused by microwave.
Traditional cooking devices on countertop are almost without exception supplied with air inlet and outlet over back panel and side panels of the outer cabinet, taking in air through air inlet for the purpose of cooling electrical components and others, and discharging through air outlet hot air with vapor emitting from foods cooked to be scattered into the thin kitchen air. Such configuration in design to place such air inlet and outlet over insignificant areas of the cabinet to counterpart inner configurations requires only ordinary engineering skills and practices.
On the other hand, built-in cooking devices, especially such as shown in the present applicant's patent document 1 above, are allowed to take in and discharge air only by way of limited square inches that could be spared apparently on the front surface, forcing severe restrictions on specialists in the trade to decide upon cooking device configurations. Based on such restrictions arising from majoring in built-in construction, the present applicant has proposed a drawer type cooking device as a built-in kitchen equipment to be built into a cabinet, wherein an air inlet portion and an air outlet portion are collectively disposed on a lower end portion on the front side of the device to thereby improve the efficiency of intake and discharge of air, improve the efficiency of cooling electric components and discharge of inside air, and to relieve the limitations of design and arrangement of the cooking device (patent document 2: Japanese patent application laid-open publication No. 2006-223337).
The concept of air flow according to the air inlet and outlet system according to the above-mentioned drawer type cooking device is as illustrated in FIG. 9. Further, FIGS. 10A and 10B show the arrangement of electric components at a depth portion of the prior art built-in cooking device, wherein FIG. 10A is a right side view and FIG. 10B is a rear view thereof. A louver for air inlet and outlet grill is disposed to cover the whole width of the cooking device body 51 at the lower front side portion of the cooking device body 51, wherein the left end portion of the front side air inlet and outlet grill is formed as an air inlet port 63. A lower side portion 59 arranged below the heating chamber 53 of the cooking device body 51 constitutes a bottom surface air inlet and outlet duct structure, wherein the left end portion of the bottom surface air inlet and outlet duct corresponding to the front side air inlet port 63 is formed as an air inlet portion 60. When a cooling fan 56 within the electric component chamber disposed at a rear portion of the cooking device body 51 is activated, cooling air F1 is taken in via the front side air inlet port 63 through the air inlet portion 60, reaches a depth portion chamber at a rear side of a depth wall of the heating chamber 53 of the cooking device body 1, and is further blown into the interior of the cooking device body 51 by the cooling fan 56.
One portion of the blow out air flow (air flow F3) from the cooling fan cools an electric component (magnetron 54), and then flows through an opening portion formed on the depth wall surface of the heating chamber 53 into the heating chamber 53 (F5), passes the interior of the heating chamber 53, and then flows through an opening portion disposed on the front side of the heating chamber into a ceiling panel air outlet duct 66 (F6). The ceiling panel air outlet duct 66 is laid horizontally toward the depth of the product on the outer side of the ceiling panel of the heating chamber (first portion 66a), and at the portion where the heating chamber ceiling panel is ended, it is bent toward the right and laid horizontally (second portion 66b), and then at the right end of the heating chamber, it is laid to bend down perpendicularly to enable air to flow into a vertical duct 67 disposed on the right end (F7 through F9). The discharged air is finally passed through an air outlet duct 61 on the right end of the bottom surface air inlet and outlet duct, and blows out to the exterior through the right end air outlet port 64 of the front side air inlet and outlet grill (F10, F11). The other air flow F4 from the cooling fan cools the electric component (high pressure transformer 55) disposed within the electric component chamber (F12), passes through the air outlet duct 62 disposed at the center of the bottom surface air inlet and outlet duct, and is discharged to the exterior through the center air outlet port 65 of the front inlet and outlet grill (F13, F14).
It is essentially rational to discharge the hot outlet air flow from the upper area of the cooking device, but since the air will be discharged toward the user, such arrangement cannot be adopted in practice. Further, if the air is discharged through a louver disposed on the lower portion of the cooking device, the hot outlet air flow will be blown out toward the user's legs. Therefore, the prior art drawer type cooking device proposes an arrangement in which an air outlet duct with a louver is disposed independently from the door, which requires an independent area for inlet air and outlet air to be formed within the limited height of the device.
However, according to the above-mentioned drawer type cooking device, the air outlet path becomes long, and the duct structure, especially the duct structure passing through the interior of the heating chamber, becomes complex and the flow path resistance is increased, and as a result, a cooling fan having a high air blow performance is required, by which the product costs and operation costs of the cooling fan are increased. Further, built-in devices must be placed in limited setting spaces having restricted heights, but since the lower duct and the louver portion take up a certain height, the height of the inner space of the cooking device had to be sacrificed corresponding to the height for ensuring independent inlet and outlet area.
Patent document 3 (Japanese patent application laid-open publication No. 2002-228163) discloses an attachment panel for a cooking device, comprising forming air blow spaces on the upper portion and the lower portion of the microwave oven being built into a closed space in a furniture instead of being placed on a counter top, forming an air inlet and outlet opening on a front side of the air blow space, and using a build-in kit for taking in air from and discharging air into the closed space, wherein the air discharged from the lower portion of the front side of the oven is directed downward so as to prevent hot air from blowing directly toward the body of the user.
If the air inlet and the air outlet of the microwave oven are separated into upper and lower areas, the object of preventing hot air from blowing toward the user can be achieved simply by directing the outlet air to flow downward. However, when air is taken in and discharged from adjacent portions on the lower area of the front side, a problem occurs in which the discharged hot air is sucked in through the air inlet and causes short circuit. Therefore, it is not only necessary to improve the arrangement of the attachment panel of the cooking device but to set the air blow speed of the outlet air, and to improve the arrangements of the inlet port and the outlet port.
Based on the trend in the field of interior designs, more and more users are putting weight on coordinating the whole kitchen with unified interior design. In the field of drawer type microwave ovens as an example of drawer type cooking devices, the drawer type microwave ovens are not subjected to price competition, but instead, are required to have high added values, so that the design thereof is required to satisfy the design expectations of the users, and that the specifications regarding performance and structure thereof must be high so as not to disappoint the high expectations of the users. Regarding physical structural conditions, the heating chamber shape of the cooking device must satisfy smooth heating and cooking operations of food and drinks preferred by the user, and the ceiling height of the heating chamber must be high enough to easily store ready-made containers and mug cups offered by various fast food shops and coffee shops. As for the size of the bottom surface of the heating chamber, in Japan, the cooking device must be large enough to store packed lunches sold in supermarkets, convenience stores and dedicated shops, whereas in the United States, the cooking device must be large enough to store at least a pizza box soled in famous pizza shops.
The present applicant has won the position of providing the one-of-a-kind microwave oven built into kitchens, since the present applicant had overcome the challenge according to the prior art and enabled the drawer type cooking device to be built into a cabinet, so it faces a new challenge of realizing higher performance and improved arrangement. As for the size of the heating chamber, the most important design challenge is to be familiar with the size demands of the users and to ensure the minimum allowable heating chamber size. In the case of built-in kitchen equipment, the installation height of the cooking device is normally within the height range from the waist to the knees of a user, and the air outlet height for discharging the warm air containing the vapor generated during cooking is set to heights corresponding to installation conditions.
As for the front-side design observed from the front side of the drawer type cooking device, the prior art devices having visible louvers are not attractive, and devices having simple, high-quality designs are desired. Louvers enable air to flow in the front-rear directions while hiding the structure on the rear side from the view of the users, and it is a function component having a plurality of louver boards extending in the horizontal direction, but it not only increases manufacturing costs, but also causes deterioration of the exterior design by the warpage of the louver boards during injection molding. Further, louver boards deteriorate the external appearance of the drawer type cooking devices and cause mismatch with the interior design of the kitchen, such as since during actual use of the product, the dust contained in the inlet air flow is collected at the front end of the louver boards, but the space between louver boards are too narrow to clean.
The problem to be solved according to the drawer type built-in cooking device is to change the air outlet structure for discharging the inside air containing heat and vapor generated during cooking of the object being heated to the exterior, and to reduce the necessary height of the air inlet and outlet structure as much as possible.
The object of the present invention is to devise the air outlet structure so as to reduce the height required for the air outlet duct and to ensure the height of the heating chamber, to thereby provide a drawer type cooking device with an attractive external appearance.